| 郯庐断裂带江苏段安丘-莒县断裂全新世活动及其构造意义 |
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| 引用本文： | 曹筠,冉勇康,许汉刚,李彦宝,马兴全,梁明剑,李西,张鹏,李丽梅.郯庐断裂带江苏段安丘-莒县断裂全新世活动及其构造意义[J].地球物理学报,2018,61(7):2828-2844. |
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| 作者姓名： | 曹筠 冉勇康 许汉刚 李彦宝 马兴全 梁明剑 李西 张鹏 李丽梅 |
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| 作者单位： | 1. 中国地震局地质研究所, 活动构造与火山重点实验室, 北京 100029;2. 河北省地震局, 石家庄 050021;3. 江苏省地震局, 南京 210014 |
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| 基金项目： | 宿迁市活动断层探测与地震危险性项目中国地震局地质研究所基本科研业务专项（IGCEA1602）和（SQZBTB20110162）共同资助. |
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| 摘 要： | 郯庐断裂带是中国东部重要的活动断裂带和边界构造带，其鲁苏段全新世活动断层的空间展布和古地震序列是地学关注的焦点问题，也是准确评价区域地震危险性的重要参数.以往研究工作多集中在郯庐断裂带地表地貌现象明显且有强震记录的山东段，而江苏段则研究程度相对较低，有关郯庐断裂带江苏段全新世活动断层范围和古地震序列问题存在争议.本文利用野外地质地貌调查、浅层地震勘探、钻孔联合剖面以及古地震探槽等多层次综合方法，重点开展郯庐断裂带江苏段全新世活动断层的分布和古地震序列研究.结果显示全新世时期，安丘-莒县断裂是郯庐断裂带江苏段的主要活动断层，且江苏全段该断层都是全新世活动断层.通过对比宿迁闸-皂河镇断裂南北安丘-莒县断裂的断层地貌和断层最新活动时间，并结合宿迁闸-皂河镇断裂在第四纪没有活动过等证据，推测该断层在全新世时期并不是区域阻碍破裂的断层.探槽揭示郯庐断裂带江苏段全新世两次古地震事件，事件Ⅰ限定在（6.2±0.3）-（13.4±0.7）ka B.P.之间，而事件Ⅱ限定在（2.5±0.1）ka B.P.到现今，全新世两次古地震间隔较长.基于构造类比法，安丘-莒县断裂具有深部孕震的构造特点，是区域未来强震的潜在发震构造.
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| 关 键 词： | 郯庐断裂带江苏段 安丘-莒县断裂 全新世活动断层 古地震 |
| 收稿时间： | 2017-02-21 |
Holocene activity of the Anqiu-Juxian fault on the Jiangsu segment of the Tanlu fault zone and its tectonics implication |
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| CAO Jun,RAN YongKang,XU HanGang,LI YanBao,MA XingQuan,LIANG MingJian,LI Xi,ZHANG Peng,LI LiMei.Holocene activity of the Anqiu-Juxian fault on the Jiangsu segment of the Tanlu fault zone and its tectonics implication[J].Chinese Journal of Geophysics,2018,61(7):2828-2844. |
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| Authors: | CAO Jun RAN YongKang XU HanGang LI YanBao MA XingQuan LIANG MingJian LI Xi ZHANG Peng LI LiMei |
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| Institution: | 1. Key Laboratory of Active Fault and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China;2. Earthquake Administration of Hebei Province, Shijiazhuang 050021, China;3. Earthquake Administration of Jiangsu Province, Nanjing 210014, China |
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| Abstract: | The Tanlu fault zone (TLFZ) is an important active structure which is a tectonic boundary in eastern China. The research on the distribution of the Holocene active faults and paleoearthquakes along the LFZ is important for seismic hazard assessment in this region, thus receiving much attention. Previous studies were primarily conducted on its Shandong segment that preserves obvious geological landforms and evidence of historical earthquakes. While the distribution of the Holocene active faults and paleoearthquakes along the Jiangsu segment remain controversial. In this paper, based on field geological and geomorphologic investigations, shallow seismic exploration, drilling and paleoseismic trenching, we reanalyze the distribution of the Holocene active faults and paleoearthquakes along the Jiangsu segment of the TLFZ.#br#The Anqiu-Juxian fault is the primary Holocene active fault along the Jiangsu segment of TLFZ evidenced by field geological investigations, shallow seismic exploration and drilling data. We suggest that this fault was active during the Holocene, while lacking reliable evidence before. Comparing the surface topography and timing of the latest activity of this fault located between the north and south of the Suqianzha-Zhaohezhen fault, as well as the evidence of fault activity in Quaternary, we consider that this Holocene active fault has not terminated to the north of the Suqianzha-Zhaohezhen fault. In other words, the Suqianzha-Zhaohezhen fault did not arrest the earthquake rupture propagation during the Holocene. Based on three paleoseismic trenches along the Anqiu-Juxian fault, we infer two events occurred in the Holocene. Event I is constrained as(6.2±0.3)-(13.4±0.7)ka B.P., and the event Ⅱ is later than(3.8±0.3)ka B.P.. We suggest that large earthquakes along the Anqiu-Juxian during the Holocene might have a relatively long recurrence interval.#br#Considering the latest studies on deep crustal structure and impact of the 1668 Tancheng earthquake (M=8.5), seismic potential on the Jiangsu segment of the TLFZ should be highly concerned. Based on the structural analogue method, we suggest that the Anqiu-Juxian fault is one of most important potential seimogenic structures within the TLFZ. |
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| Keywords: | Jiangsu segment of the Tanlu fault zone Anqiu-Juxian fault Holocene active fault Paleoearthquake |
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